Re: Flashers

[Tom Droege <tdroege2@earthlink.net>]

No, I see increases in the both channels on the same exposure.

Hmmm!  There is the possibility of parallax.  As I noted, the bright hit is 
sometimes displaced.

To repeat, there are simultaneous increases.  Sometimes more than one in 
the daily measurements.  i.e. I measure a star every time the sky is clear 
and it transits the meridian.  I have at least 10 and as many as 40 single 
nightly measurements in the data base I am studying.  Most often there is a 
single high point in the V and I channels for one night.  But sometimes 
more than one night has a high measurement.

While this could be a "bad night", there are not so many of these.   A bad 
night might make all the measurements for the night high.  I would get tens 
of thousands of such stars in that case.  Besides, some of these are of 
order a mag, and that is more than the probable error for the worst data 
analyzed.

Tom Droege

At 10:07 AM 5/18/03 -0700, Arne Henden wrote:
>George Turner's suggestion of cosmic ray hits is the most
>likely answer.  Faser's events are all possible, but with
>low probability.  Tom's idea of plane lights won't work (you
>would see the parallax between two cameras).  I also assume
>that you see this in only one of the two cameras, right?
>Arne
>
>Fraser Farrell wrote:
>>Tom Droege wrote:
>>
>>>Are there many stars that flash?  I keep finding stars with one bright
>>>point.
>>
>>TASS Press Release : the Mark IV discovers gravitational lens events....  :-)
>>
>>Three of the four astronomical possibilities that come to mind can all be 
>>dismissed:
>>  - Pulsars. Not bright enough (optically), and they would flash many 
>> many times during a single Mark IV exposure.
>>  - Gamma ray burst's optical counterpart. This might explain those 
>> occasional "seen once and never again" stars.
>>  - Dwarf novae outbursts typically go on for hours, sometimes days. Lots 
>> of these potentially detectable by TASS. But if you're taking many 
>> images per night of a dwarf nova, you would see it "bright" on several 
>> consecutive images.
>>The fourth possibility is red dwarfs that are Flare Stars. These are 
>>detectable as occasional outbursts of light & radio waves that last 10-30 
>>minutes. Proxima Centauri, for example, can brighten from its usual mag 
>>11 up to mag 9 during a flare. Quite a sight if you're lucky enough to see one!
>>
>>cheers,
>
>